In detail

OPC stands for oligomeric proanthocyanidins, a group of condensed tannins found in grape seeds, pine bark, and other plants. Commercial extracts are often specified at 95% OPC by UV, sometimes alongside a total polyphenol value. The method is a family measurement, not a single-compound assay.

Species and raw material matter. French maritime pine bark and Chinese masson pine bark are different starting materials, and grape seed OPC is a different ingredient again. If the brand story names a specific source, the specification and traceability record should support it.

Why it matters to a buyer

  • It is the usual label marker for grape seed and pine bark products.
  • UV family totals can vary with method and reference standard.
  • Source and species claims require documentation.

What to ask a supplier

01

Is the OPC result by UV or HPLC, and against which standard?

02

What is the botanical species and plant part?

03

Can you provide a polyphenol profile in addition to the total?

Cite this page

Rainwood Botanical. "Oligomeric proanthocyanidins." Botanical extract glossary, October 2026. https://ingredients.rainwoodbio.com/resources/glossary/opc/